TY - BOOK AU - Diansuy,Marivique . TI - Isolation of Mindanao Bacillus thuringiensis (Berliner) strains and preliminary bioassay against lepidopteran species PY - 2002/// KW - Undergraduate Thesis KW - BIO200, KW - BSB N1 - Thesis (BS Biology) -- University of the Philippines Mindanao, 2002 N2 - Soil and leaf samples collected from Davao City, Bukidnon and Compostela Valley were suspended in Luria-broth-sodium acetate solution, heat-treated, diluted and spread-plated onto L-agar medium. After 3-5 days of incubation at room temperature, colonies typical of Bacillus thuringiensis (Bt) were observed. These colonies were transferred and streak-plated onto T3 medium and grown at the same condition. A total of 28 Bt isolates were obtained. Among these, 21 isolates came from soil samples. The protein concentration of spore-crystalline suspensions of 20 randomly selected isolates were determined and preliminary bioassay was carried out against the diamond back moth (Phutella xylostella) larvae using suspensions containing 2g/ml protein. Seven isolates produced 100% mortality after 7 days incubation, five of which were isolated from cornfields relatively free from corn borers. It is recommended that more thorough bioassays be conducted and that the Bt isolates be characterized further in order to determine which specific Cry toxin proteins are produced by the isolates ER -